>>19197296>The BadStark Mountain, slow traversing speed (snow, mud, surf), Diamond/Pearl's lack of variety.
>The GoodMost everything else.
Platinum in particular was really well thought out. Even the NPCs had mons and movesets that were appropriately challenging (while still being fodder) with thoughtfully challenging 'boss' tier battles (Skuntank, some Gym leader's main mons, etc). Normally, it's hard to see when you're 1/2HKOing all the mons, but I came to really appreciate the planning in my mono-Grass run of Platinum (since Grass isn't 2HKOing for jack early/mid game).
Good lore, Cyrus was compelling as a literal autist esp. when he stops pretending to be a decent person, the Poketch is still the best utility tool of any gen, good ingame length, good postgame, and with Platinum had good variety of mons to catch and battle (Fire E4 in Diamond/Pearl was simply embarrassing). As for gameplay, Phys/Spec split was probably the best thing to happen in a long time and introduced a more well rounded set of moves for all types (at least a 70/80 base move for Phys/Spec for each type; no more relying on HP Bug/Flying for STAB) on top of the fantastic tutors that now set the standard for what a tutor set should offer.
I still have reservations on Diamond and Pearl, and HGSS while being the most polished game in the series still suffers from being a remake of the poorly paced Gen 2. However, for me, Platinum defines Gen 4 and it's quite the marvel as an entry into the series. There's just so much it does right.
